In recent years, a small and inexpensive, IEEE 802.15.4 standard-compliant communication device capable of performing low-power digital radio communication is used in a wireless network.
In an IEEE 802.15.4 standard-compliant network, a tree-type topology is adopted which is configured of a CS (collection state), and at least one node.
In a tree-type topology, a lower node relays data to an upper node or the CS while combining pieces of data as necessary.
In such data relaying, since a plurality of pieces of data concentrates on a node which relays data, a data collision occurs, and therefore the success rate of data collection may lower in some cases.
In order to solve such a problem, collision frequency is lowered by combining a plurality of pieces of data to be relayed and thus reducing the number of times that data is transmitted (refer to Non Patent Literature 1).